I noticed this when I changed to my Focus from a Renault Scenic. It was just a case of adapting clutching technique. Lift off the accelerator slightly earlier than you normally would before depressing the clutch.

Got the horn off today (no jokes please!!) and it was filled with water, emptied it out and dried it and it was fine. The culprit awas a huge chunk taken from the passenger side wheel arch liner which I hadn't noticed before, so gonna keep an eye on that and try to get a new one.